Bio-Based Furan-Polyesters/Graphene Nanocomposites Prepared by In Situ Polymerization

Abstract

In situ intercalative polymerization has been investigated as a strategic way to obtain poly(propylene 2,5-furandicarboxylate) (PPF) and poly(hexamethylene 2,5-furandicarboxylate) (PHF) nanocomposites with different graphene types and amounts. Graphene (G) has been dispersed in surfactant stabilized water suspensions. The loading range in composites was 0.25–0.75 wt %. For the highest composition, a different type of graphene (XT500) dispersed in 1,3 propanediol, containing a 6% of oxidized graphene and without surfactant has been also tested. The results showed that the amorphous PPF is able to crystallize during heating scan in DSC and graphene seems to affect such capability: G hinders the polymer chains in reaching an ordered state, showing even more depressed cold crystallization and melting. On the contrary, such hindering effect is absent with XT500, which rather induces the opposite. Concerning the thermal stability, no improvement has been induced by graphene, even if the onset degradation temperatures remain high for all the materials. A moderate enhancement in mechanical properties is observed in PPF composite with XT500, and especially in PHF composite, where a significative increase of 10–20% in storage modulus E’ is maintained in almost all the temperature range. Such an increase is also reflected in a slightly higher heat distortion temperature. These preliminary results can be useful in order to further address the field of application of furan-based polyesters; in particular, they could be promising as packaging materials.

In Situ Synthesis, Crystallization Behavior, and Mechanical Property of Biobased Poly(hexamethylene 2,5-furandicarboxylate)/Multiwalled Carbon Nanotube Nanocomposites

“…Obviously, both graphene and silica accelerated the crystallization of PHF by acting as nucleation agents . Vannini et al also reported the preparation of PHF composites by introducing graphene with different types and amounts . An increase of around 10–20% in the storage modulus was detected in PHF composites, indicating that a better interfacial between graphene and matrix was formed through the in situ method …”

“…Compared to those of PEF and poly(propylene 2,5furandicarboxylate) (PPF), the lower T p and T m of PHF are considered an advantage in reducing energy consumption during melt processing. 6,11,21,26 In addition, PHF showed a comparable toughness with relatively high elongation at break of around 200%. 20 Moreover, PHF exhibited a faster crystallization rate than PEF, PPF, and poly(neopentyl glycol furandicarboxylate) (PNF).…”

“…35 However, only a few studies on the crystallization of PHF have been reported. 26,27,36 For instance, Bikiaris et al studied the isothermal crystallization and subsequent melting behavior of PHF. 27 They reported PHF displayed a crystallization halftime between 0.45 and 16.62 min and the Avrami exponent n between 2.0 and 2.3.…”

“…26 An increase of around 10−20% in the storage modulus was detected in PHF composites, indicating that a better interfacial between graphene and matrix was formed through the in situ method. 26 In this work, two biobased PHF/MWCNT composites were prepared via an in situ process for the first time. The contents of MWCNTs were 0.25 and 0.5 wt %, respectively.…”

“…The equilibrium melting temperature and the heat of fusion for pure crystalline PHF were further reported to be 157 °C and 143 J/g, respectively, by Papageorgiou et al The melt crystallization temperature ( T p ) of PHF was determined to be about 80 °C. Compared to those of PEF and poly­(propylene 2,5-furandicarboxylate) (PPF), the lower T p and T m of PHF are considered an advantage in reducing energy consumption during melt processing. ,,, In addition, PHF showed a comparable toughness with relatively high elongation at break of around 200% . Moreover, PHF exhibited a faster crystallization rate than PEF, PPF, and poly­(neopentyl glycol furandicarboxylate) (PNF). ,, Due to the high crystallinity degree and specific ring flipping, PHF displayed comparable gas barrier properties against O 2 and CO 2 compared to those of PEF. ,, In conclusion, PHF may be widely employed in packaging applications and agricultural films.…”